This example places our triads on the third, fourth and fifth strings to accommodate this I - IV - V progression in A. You'll start with a root position A triad, coming out of the C form of the CAGED system. Next up you have a D chord coming out of your E form. Using your third finger as a guide, move down and grab the first inversion E chord that is derived from the G form. Try playing these same exact triads at different places on the neck to get different tonal qualities.